Single motor upright vacuum cleaners are well-known in the art. Such upright vacuum cleaners typically have a nozzle assembly which contains the blower motor, a rotating agitator brush and a suction nozzle opening adjacent the brush. The suction is created by an impeller or suction fan turned by the blower motor and mounted within an impeller housing. As the blower motor turns, a negative pressure or suction is created which is delivered to the suction nozzle opening by a vacuum plenum in the nozzle housing. Conventionally, the suction at the nozzle opening causes dust and particulate matter to flow from the agitator brush, through the vacuum plenum to the impeller housing and thereafter to the dust bag where it is collected.
Typically, in an upright vacuum cleaner the dust bag is flexible and can be mounted on the outside of the handle assembly. In order to use the vacuum cleaner comfortably, the handle assembly must rotate relative to the nozzle assembly. Thus, it is necessary to provide a means by which the connection of the dust bag to the nozzle assembly can accommodate this rotation. Early upright vacuum cleaners such as that shown in U.S. Pat. No. 1,235,920, rigidly connect the opening of the flexible dust bag directly to the output of the impeller housing of the nozzle assembly. The flexibility of the dust bag allows the handle assembly to rotate relative to the nozzle assembly. However, when the blower motor is turned on, the dust bag inflates becoming less flexible and making it difficult to rotate the handle assembly relative to the nozzle assembly thereby placing undue stress on the dust bag in the area of its connection to the impeller housing, potentially causing premature failure of the dust bag.
Later, vacuum cleaners utilized blower motors mounted to the nozzle assembly and a flexible conduit between the output of the impeller housing and the open end of the dust bag. Such arrangements have the disadvantage of requiring a flexible coupling which is susceptible to wear and ultimately leaking pressurized air containing dust and other particulate matter.
More recently, in order to provide a more durable seal between the dust bag and the output of the impeller housing, upright vacuum cleaners have incorporated handle assembles with a central conduit rigidly mounted to the output of the impeller housing of the blower at one end, and to the dust bag at the other. In order to allow rotation of the handle assembly, the blower motor is rotatably mounted within the nozzle assembly so that rotation of the handle assembly and the associated central conduit relative to the nozzle assembly causes the blower motor and integral impeller housing to rotate as well. The disadvantage of such arrangement is that the wiring to the blower motor is caused to flex each time the handle assembly is rotated, contributing to chafing and early failure of the electrical wiring.
U.S. Pat. No. 3,199,138 discloses an upright vacuum cleaner construction in which the handle assembly has a central conduit which is fixedly mounted to the output of the impeller housing. The impeller housing is mounted to the blower motor in a manner which allows relative rotation of the impeller housing and handle assembly to the blower motor while the blower motor remains fixedly mounted within the nozzle assembly. However, the disadvantage of such construction is that in order to centrally mount the handle assembly to the nozzle assembly, the blower motor is mounted remotely from the center line of the nozzle assembly Thus, when the vacuum cleaner is pushed and pulled over the floor, there is a substantial torque created about the handle axis making it less comfortable to use the vacuum cleaner.
Moreover, the blower assembly taught by U.S. Pat. No. 3,199,138 does not include integral side walls which rotate with the assembly. Rather, the annular bearings which permit rotation of the assembly housing incorporate relatively large diameter sealing elements. These sealing elements diminish the strength of the bearings because of their inherent flexibility and may be prone to leakage if the handle assembly is moved obliquely to its axis of rotation, which would likely occur while manipulating the vacuum cleaner during operation.
Upright vacuum cleaners utilizing flexible dust bags must have mounting means for such dust bags which will accommodate shortening of the dust bag as the bag is caused to inflate by the air passing through the impeller housing. An early mounting means construction is disclosed in U.S. Pat. No. 1,235,920. More recent constructions include a bag hanger having opposed bag supporting arms inserted into cavities formed by the side pleats of a flexible dust bag stitched closed at the top as taught by U.S. Pat. No. 4,349,361. Therein, the bag hanger is secured to a rigid bar casing which serves to cover both the top portion of the bag and to anchor a hook shaped wire for connection to the handle assembly. Similarly, U.S. Pat. No. 4,566,884 discloses an upper bag retainer system wherein the flexible dust bag is secured between a bag support plate and a bag cover. U.S. Pat. No. 5,007,133 discloses an upper bag retainer system wherein the bag is stitched closed at its top with several cloth loops stitched into the top portion. A mounting bar is inserted through the loops for connection to the handle assembly. Each of these devices has the disadvantage of being comprised of numerous parts and results in increased costs to produce due to the need for substantial assembly or installation or the additional operation of stitching loops to the top of the dust bag.
An upright vacuum cleaner having a rotating brush mounted within the nozzle assembly requires a means to adjust the height of the nozzle assembly and rotating brush to account for variations in the height of floor coverings so that the vacuum cleaner will effectively remove dust and particulate matter from low pile carpeting such as indoor/outdoor carpeting and high pile or deep shag type carpeting. Such devices are well-known. For example, the adjusting device taught by U.S. Pat. No. 2,677,850 incorporates a lever which adjusts the height of the nozzle assembly and U.S. Pat. No. 3,654,661 incorporates a lever controlled cam which adjusts the height of the rear wheels of the nozzle assembly. The first mechanism requires two hands for operation and can be inadvertently changed by the application of pressure to the front of the nozzle assembly. The other mechanism has the disadvantage of being mounted at the rear of the nozzle assembly of the vacuum cleaner where the operator's view of the adjustment is obstructed by the flexible dust bag.
The rotating brush in an upright vacuum cleaner is generally caused to rotate by a drive belt or other flexible drive means connecting the blower motor to the brush. To avoid injury to the operator of the vacuum cleaner if the nozzle assembly is turned over or lifted up, and to prevent long pile carpeting from becoming entangled in the rotating parts, it is necessary to provide a cover for the rotating parts. However, as it will be necessary to repair or replace the drive belt, such cover must be readily removable; preferably without the use of tools. Because the bottom of the nozzle assembly is subjected to significant vibration, prior art latching means which were removable without the use of tools and lacking a positive operation did not prevent the latch from opening inadvertently due to such vibration. Furthermore, prior art latching means can be opened by children exposing the drive belt and creating a potentially dangerous condition.